Musings on MPG

My current piece for Traffic Technology International is about steps being taken by car makers to reduce fuel consumption and emissions. Today I took delivery of a Skoda Fabia Greenline (same 1.4 diesel engine, "taller" gears and aerodynamic modifications as VW Polo Bluemotion or Seat Ibiza Ecomotive). Fuel consumption showed 54.6 mpg when I started my journey from Bicester. By the time I reached Staines (driving gently), it was reading 75.8mpg.